Positive-working photoresist process employing a selected mixture of ethyl lactate and ethyl 3-ethoxy propionate as casting solvent during photoresist coating

Claim 1

The process of developing an image-wise exposed positive-working photoresist-coated substrate comprising: (1) coating said substrate with a light-sensitive composition useful as a photoresist, said composition comprising an admixture of: (a) at least one alkali-soluble binder resin; (b) at least one photoactive compound; (c) a sufficient amount of a solvent mixture comprising ethyl lactate and ethyl 3-ethoxy propionate to dissolve (a) and (b); wherein the amount of said binder resin is from about 60% to 95% by weight, the amount of said photoactive compound is from about 5% to about 40% by weight, both based on the total solids contents of said light-sensitive composition, and wherein the weight ratio of ethyl lactate to ethyl 3-ethoxy propionate is from 30:70 to about 80:20, and wherein said substrate is a silicon-containing wafer having a diameter of at least 6 inches; (2) subjecting said coating on said substrate to an image-wise exposure of radiant light energy; and (3) subjecting said image-wise exposed coated substrate to a developing solution to form a positive image-wise pattern in the coating.